Five Variables

Source: AtCoder

Problem Statement

Initially $x_i=i$ for $1\le i\le5$. Exactly one variable is then assigned $0$. Given the five final values, determine which variable was changed.

Input

One line contains $x_1,x_2,x_3,x_4,x_5$.

Output

Print the index $i$ of the variable whose value is $0$.

Subtasks

• Subtask 1 (100%): The input is guaranteed to be a possible result of the described operation.

Examples

Example 1

Input

0 2 3 4 5

Output

1

Explanation

For the sample values 0, 2, 3, 4, 5, evaluating the conditions in the statement gives 1. Therefore the program prints the shown output.

Example 2

Input

1 2 0 4 5

Output

3

Explanation

For the sample values 1, 2, 0, 4, 5, evaluating the conditions in the statement gives 3. Therefore the program prints the shown output.